Blue dye and process of making same.



stuffs.

N ITE- ARTHUR WEINBERG AND FELIX KLINGEMANN, OF FRANKFORT-ON-THE- MAIN,GERMANY, ASSIGNORSTO LEOPOLD CASSELLA 82; CO., OF FRANK-FORT-ON-THE-MAIN, GERMANY.

BLUE DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 709,186, datedSeptember 16, 1902.

Application filed December 31, 1901. Serial No. 87,957. (Specimens) Toall whom it may concern:

Be it known that we, ARTHUR WEINBERG and FELIX KLINGEMANN, citizens ofPrussia, and residents of Frankfort-on-the Main, in the Province ofHesse-Nassau and Kingdom of Prussia, Germany, have invented certain newand useful Improvements in Blue Dyestuffs and Processes of Making Same,of which the following is a specification.

Our invention relates to an improvement in the production of directdyeing cotton dye- We have found that a blue color of an extremefastness to light is obtained by first combining three molecules of 1.6or 1.7 naphtylamin sulfo-acid (which are generally designated as Cleveacids) to a new sub-' stance of the constitution,

diazotizing this compound and finally combining with 2.5 amidonaphtol 7sulfonic acid. If the hydrogen in the molecule I of the formula givenabove, which is in position 1:4 to the amido or diazo group, issubstituted by acetamido or amido, the character of the dyestufi is notvery essentially altered.

The following examples illustrate how this invention may be carried intoeffect:

Example 1: 24.5 kilos of the sodium salt of the naphtylamin sulfo-acid1.6 or 1.7 (Cleve acid) are diazotized at 5 centigrade with 34.5 kiloshydrochloric acid and 6.9 kilos nitrite of sodium. The resulting diazosolution is allowed to run into a solution of 24.5 kilos sodium salt ofthe Cleve acid cooled to 0 centigrade. After twelve hours it is furtherdiazotized at 0 centigrade with twenty-three kilos hydrochloric acid and6.9 kilos nitrite of sodium. After an hour the diazo solution isintroduced into a solution containing 24.5 kilos of the sodium salt ofCleve acid and twenty-eight kilos sodium acetate. After twelve hourstheintermediate substance (consisting of three molecules of Cleve acid)is separated by addition of common salt. It is then filtered oif anddissolved in boiling water. To the cooled solution fifty kilos hyof 2amido 5 naphtol 7 sulfonate of S,Q(1L, 55

containing, besides, fifty kilos carbonate of soda. As soon as theformation of the blue dyestuff is completed the solution is heated to 85centigrade and the dyestuffs precipitated by means of common salt.

Example 2: Twenty-eight kilos 1.4L amido acetnaphtalid 7 sulfo acid arediazotized with seven kilos nitrite of soda and thirtysix kiloshydrochloric acid. The diazo compound is combined with 22.3 kilos Cleveacid in the presence of an excess of acetate of soda. After about twohours the easilysoluble brown monoazo dyestuif is formed. Itis thenacidulated with hydrochloric acid and diazotized again by adding sevenkilos nitrite of soda. The resulting diazo compound is allowed to runinto the solution of 22.3 kilos Cleve acid in the presence of asufficient quantity of sodium acetate to neutralize the freemineralacid. Thethus-formed violet dyestutf is easily soluble, and it isbest to use its solu tion directly for the further diazotizing,which isdone by acidulating with hydrochloric acid and introducing seven kilosnitrite of soda. The diazo compound is brought into the solution of 23.9kilos 2 amido 5 naphtol 7 sulfonic acid, rendered alkaline by means ofcarbonate of soda. The blue dyestuff is finally salted out and dried, orthe acetyl group may be saponified by boiling the solution for abouthalf an hour with soda-lye of five percent. The excess of lye is thenfinally neutralized with an acid and the dyestuff precipitated withcommon salt;

The thus-produced dyestuffs show the following properties: In thedrystate they represent dark powders of a metallic luster. They aresoluble in water, with a blue color. From the aqueous solutionhydrochloric acid precipitates the acid of the coloring-matter in shapeof blue flakes. Acetic acid does not precipitate the coloring-matter.The solution of the new dyes in concentrated sulfuric acid shows ablackish-blue color. On addition of water the coloring-matter isprecipitated in form of violet flakes. They produce on unmordantedcotton indigo blue shades of a remarkable fastness to light.

Having now described our invention and in what manner it may be carriedout, what we claim is-- 1. The process of producing blue cottondyestuffs of the herein-d escribed constitution which consists indiazotizing one molecule of amido acetnaphtalid sulfo-acid, combiningsuccessively with two molecules of Cleve acid, diazotizing again andfinally combining with one molecule of 2 amido 5 naphtol 7 sulfonic acidsubstantially as described.

2. The blue cotton dyestuff of the constitution mentioned above which isa dark-blue or bronzy powder easily soluble in water with a bright bluecolor, being precipitated by addition of hydrochloric acid, dissolvingwith a blackish-blue shade in concentrated sulfuric acid, separatingfrom such solution by addition of water and dyeing unmordanted cottonindigo-blue shades fast to light substantially as described. v Signed atFrankfort-on-the-Main, in the Province of Hesse-Nassau, Kingdom ofPrussia, this 11th day of December, A. D. 1901.

' ARTHUR WEINBERG. FELIX KLINGEMANN. Witnesses:

JEAN GRUND, CARL GRUND.

